1. Field of the Invention
The present invention relates to golf balls. More particularly, the present invention relates to multi-piece golf balls having a center, a mid layer and a cover.
2. Description of the Related Art
Golf balls make a flight with accompanying back spin. Upon shots with an iron club, sufficient back spin leads to suppression of run of the golf ball after landing. The back spin is responsible for control performances upon shots with an iron club.
Top concern to golf players for golf balls is their flight performances. The golf players prefer golf balls which can achieve great flight distances upon shots with a driver. Excess spin impairs the flight performances upon shots with a driver. Golf balls which can be accompanied by suppressed spin upon shots with a driver have been demanded.
The golf players place great importance also on feel at impact of the golf balls. Thus, the golf players prefer soft feel at impact. Achievement of both favorable flight performances and feel at impact has been desired.
Japanese Unexamined Patent Application Publication No. Hei 11-417 discloses a golf ball including a core and a cover. This core has an inner layer and an outer layer. The inner layer is constituted with a thermoplastic elastomer. This inner layer has a great hardness. This inner layer impairs feel at impact. The inner layer having a great hardness is not responsible for suppression of the spin caused upon shots with a driver. This golf ball is inferior in flight performances.
Japanese Unexamined Patent Application Publication No. Hei 11-57070 (U.S. Pat. No. 6,071,201) discloses a golf ball having a core and a cover. This core has an inner layer and an outer layer. The inner layer is constituted with a resin, while the outer layer is constituted with a rubber composition. This inner layer has a great hardness. This inner layer impairs feel at impact. The inner layer having a great hardness is not responsible for suppression of the spin caused upon shots with a driver. This golf ball is inferior in flight performances.
Japanese Unexamined Patent Application Publication No. 2000-229133 (U.S. Pat. No. 6,605,009) discloses a golf ball having a core and a cover. This core has a central core (center) and an outer layer. The central core is constituted with a thermoplastic resin, while the outer layer is constituted with a rubber composition. This central core has a diameter of 3-15 mm. This central core is so small that it is not responsible for the feel at impact enough. This central core has a hardness greater than that of the outer layer. According to this golf ball, the spin is not suppressed enough.
Japanese Unexamined Patent Application Publication No. 2001-17571 (U.S. Pat. No. 6,394,912) discloses a golf ball having a core and a cover. This core has a center and an outer layer. The center is constituted with a thermoplastic resin. This center has a diameter of 3-18 mm. This center is so small that it is not responsible for the feel at impact and flight performance enough.
Golf players desire for further improvement of various performances of golf balls. An object of the present invention is to provide a golf ball that is excellent in the flight performances and feel at impact.